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    Subject[PATCH 0/4] new driver for TI eQEP
    Date
    This series adds device tree bindings and a new counter driver for the Texas
    Instruments Enhanced Quadrature Encoder Pulse (eQEP).

    As mentioned in one of the commit messages, to start with, the driver only
    supports reading the current counter value and setting the min/max values.
    Other features can be added on an as-needed basis.

    The only other feature I am interested in is adding is getting time data in
    order to calculate the rotational speed of a motor. However, there probably
    needs to be a higher level discussion of how this can fit into the counter
    subsystem in general first.

    This series has been tested on a BeagleBone Blue with the following script:

    #!/usr/bin/env python3

    from os import path
    from time import sleep

    COUNTER_PATH = '/sys/bus/counter/devices'
    COUNTERS = ['counter0', 'counter1', 'counter2']
    COUNT0 = 'count0'
    COUNT = 'count'
    CEILING = 'ceiling'
    FLOOR = 'floor'
    ENABLE = 'enable'

    cnts = []

    for c in COUNTERS:
    enable_path = path.join(COUNTER_PATH, c, COUNT0, ENABLE)
    with open(enable_path, 'w') as f:
    f.write('1')
    ceiling_path = path.join(COUNTER_PATH, c, COUNT0, CEILING)
    with open(ceiling_path, 'w') as f:
    f.write(str(0xffffffff))

    cnt_path = path.join(COUNTER_PATH, c, COUNT0, COUNT)
    cnts.append(open(cnt_path, 'r'))

    while True:
    for c in cnts:
    c.seek(0)
    val = int(c.read())
    if val >= 0x80000000:
    val -= 0x100000000
    print(val, end=' ')
    print()
    sleep(1)

    David Lechner (4):
    dt-bindings: counter: new bindings for TI eQEP
    counter: new TI eQEP driver
    ARM: dts: am33xx: Add nodes for eQEP
    ARM: dts: am335x-boneblue: Enable eQEP

    .../devicetree/bindings/counter/ti-eqep.txt | 18 +
    MAINTAINERS | 6 +
    arch/arm/boot/dts/am335x-boneblue.dts | 54 +++
    arch/arm/boot/dts/am33xx-l4.dtsi | 27 ++
    drivers/counter/Kconfig | 12 +
    drivers/counter/Makefile | 1 +
    drivers/counter/ti-eqep.c | 381 ++++++++++++++++++
    drivers/pwm/Kconfig | 2 +-
    8 files changed, 500 insertions(+), 1 deletion(-)
    create mode 100644 Documentation/devicetree/bindings/counter/ti-eqep.txt
    create mode 100644 drivers/counter/ti-eqep.c

    --
    2.17.1

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